Parameters

Return Values

An integer greater than zero indicates the number of rows affected or
retrieved.
Zero indicates that no records were updated for an UPDATE statement, no
rows matched the WHERE clause in the query or that no
query has yet been executed. -1 indicates that the query returned an
error.

Note:

If the number of affected rows is greater than the maximum integer value( PHP_INT_MAX ), the
number of affected rows will be returned as a string.